TRISNITRATE OF BISMUTH.

501

medica of the Dublin Pharmacopoeia, but for what reason I cannot divine,since it is never used in medicine.

Order 22.—Bismuth and its Compounds.

Bismu'thum. — Bis'muth.

History. —This metal is first mentioned by Agricola, in 1529. It hasbeen termed Marcasita, Tectum Argenti, or, by the Germans, Wismuth .“ The old miners called it Wismuth, ” says Matthesius, “ because itblooms as a beautiful meadow ( Wiesematte ), on which variegated flowersof all kinds are glittering,” (Schwartze, Pharm. Tabellen ).

Natural History. —Bismuth occurs only in the mineral kingdom. Itis found in Cornwall, Saxony , Bohemia, &c. It is met with in the me-tallic state nearly pure ( native bismuth), and in combination with sul-phur and with oxygen.

Preparation, —It is chiefly obtained from native bismuth by meltingthe metal out of its gangue.

Properties. —It is a reddish white metal, without taste or smell, com-posed of brilliant broad plates, and readily crystallizable in cubes orregular octahedrons. Its sp. gr. is 9'83 to 9'88. It is moderately hard,brittle, pulverizable, fusible at 476° F. When strongly heated in the airit takes fire, and burns with a faint blue flame, emitting a yellow smoke(the oxide). In close vessels it maybe volatilized. Its equivalent is 72.

Characteristics. —It is distinguished by its brittleness, its readyfusibility, its solubility in nitric acid, and by the characters of the nitricsolution, which throws down a white precipitate on the addition ofwater, and a black one when hydro sulphuric acid or the hydrosulphatesare added to it.

Purity. — Any arsenicum, which may be mixed with bismuth, isinsoluble in nitric acid: it is converted by the acid into an insolublearseniate. Copper may be detected by precipitating the nitric solutionwith ammonia ; the supernatant liquor is blue if copper be present.

Physiological Effects and Uses. —In the metallic state, bismuth isinert. Its only use is in the preparation of the trisuitrate.

Bismu'thi Trisni'tras. — Trisni'trate of Bis'muth.

History. —This compound was first prepared by Lemery. It has hadvarious appellations, such as pearl or flake white, magistery of bismuth(also a name for submuriate of bismuth), Spanish white, subnitrate ortetarto-nitrate of bismuth.

Preparation. —In the London Pharmacopoeia it is directed to heprepared by dissolving one ounce of bismuth in a fluid ounce and a halfof nitric acid, to which six drachms of water have been added. Afterthe solution has been filtered, about three pints of distilled waterare to be added: the subnitrate precipitates, and is to be collected,washed, and dried.

In the Dublin Pharmacopoeia, seven parts of bismuth are dissolved intwenty parts of diluted nitric acid, and the solution added to a hundredparts of water.

In the first part of this process we obtain a nitrate of bismuth by the